Porous copolymer resins

ABSTRACT

Vinyl halide copolymer resins having relatively high porosity levels are produced by polymerizing a vinyl halide with a comonomer of an acrylated caprolactone. The product produced exhibits high absorbtivity of plasticizer, easy processability and films made therefrom have low fish-eye content.

This is a divisional of copending application Ser. No. 07/200,496 filedon 5/31/88, now U.S. Pat. No. 4,871,780 issued 10/3/89.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates to vinyl halide copolymer compositions havinggood porosity properties. More specifically, this invention relates tocopolymers of vinyl chloride and acrylated caprolactones which exhibithigh porosity levels, high absorbtivity of plasticizer, easyprocessability and excellent moldability.

2. State of the Art

It is well-known that polyvinyl chloride (PVC) is one of the most usefulmaterials known because of its superior chemical, physical andmechanical properties. It is also well established that PVC is one ofthe most modifiable plastic materials in existence. Consequently, PVC isused in large volumes because it can be modified to desiredspecifications to make specific molded end products. In choosing themethod and materials for modifying PVC for particular moldingapplications, it is important that the chemical, physical and mechanicalproperties inherent in PVC be retained.

In one technique to improve upon the phsical and mechanical propertiesof PVC, vinyl chloride monomer is copolymerized with various comonomersto achieve certain desired properties, such as improved processability.For example, it is well-known that the copolymerization of vinyl acetatewith vinYl chloride results in a copolymer with improved processabilityover homopolymers of vinyl chloride. While this approach is advantageousin many applications, one of the problems encountered is that certain ofthe desirable properties inherent in the vinyl chloride homopolymer maybe lost at the expense of the copolymerization. For example, insuspension polymerization, the PVC homopolymer particles produced aregenerally porous. Porosity is a very important property of the resinparticles because it not only allows the polymerized resin particles tobe easily stripped of its residual monomer thereby making it easier tocomply with worker safety standards, but also gives the resin theability to absorb large quantities of plasticizers. However, unlike PVChomopolymer, copolymers of vinyl chloride and vinyl acetate are "glassy"(e.g., lack porosity). Vinyl chloride copolymers made with 3 to 6 weightpercent of vinyl stearate or other vinyl ester comonomers have beenfound to have very low porosity levels (below 0.10 ml/g as measured bymercury intrusion). In addition, unfavorable phenomenon such as thefusion of primary resin particles occurs during the polymerizationreaction. Scanning electron microscopy (SEM) has revealed that acomplete fusion of primary resin particles occurs during thecopolymerization of vinyl chloride and vinyl acetate at conversionlevels of 5 to 8 percent. Low resin porosities coupled with the fusionof primary resin particles leads to low level plasticized resins ofirregular shape.

U.S. Pat. Nos. 3,945,958; 3,951,925 and 4,695,616 all disclose attemptsto produce vinyl chloride polymers and copolymers having improvedporosity. However, the methods disclosed therein require extremelyspecific suspending agents, catalysts and additives, as well as strictcontrol over process conditions. No attempt is made to improve resinporosity through comonomer systems.

It would be highly desirable to provide a vinyl chloride copolymer resinwith improved porosity and morphology properties that is easilypolymerized using conventional polymerization additives and techniques.It would also be desirable to have a copolymer resin that is amenable toprocessing in the formation of molded articles.

SUMMARY OF THE INVENTION

Accordingly, it is an object of this invention to provide a porous vinylhalide copolymer resin that is superior in the absorptivity ofplasticizers.

It is a further object of this invention to provide a vinyl halidecopolymer resin that is easily processable and moldable into desired endproducts.

It is still a further object of this invention to provide a copolymerresin that will not agglomerate or fuse together during polymerization.

Yet a further object of this invention is to provide a molded (e.g., byextrusion or injection molding) article having excellent physicalproperties.

Another object of this invention is to provide a method for preparing aporous vinyl halide copolymer resin of varying molecular weights.

These and other objects are accomplished herein by a vinyl halidecopolymer resin comprising repeating units of vinyl halide and acrylatedcaprolactone, wherein the vinyl halide is present in the amount of about80 to 99 percent by weight and the acrylated caprolactone is present inthe amount of about 20 to 1 percent by weight of the total comonomer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a through 1e are light reflectance photographs at 44×magnification of PVC, vinyl chloride/vinyl acetate and vinylchloride/acrylated caprolactone resins.

FIG. 1a is a photograph of PVC homopolymer resin.

FIG. 1b is a photograph of vinyl chloride/acrylated caprolactonecopolymer resin containing 2.2 wt. % TONE M-100 acrylated caprolactone.

FIG. 1c is a photograph of vinyl chloride/acrylated caprolactonecopolymer resin containing 10.9 wt. % TONE M-100 acrylated caprolactone.

FIG. 1d is a photograph of vinyl chloride/vinyl acetate resin containing2.2 wt. % vinyl acetate.

FIG. 1e is a photograph of vinyl chloride/vinyl acetate resin containing5.4 wt. % vinyl acetate.

FIGS. 2a through 2d are scanning electron micrographs (SEM) of vinylchloride/acrylated caprolactone, vinyl chloride/vinyl acetate and vinylchloride/ethylhexyl acrylate resins.

FIG. 2a SEM at 500X showing a cross-sectional view of a vinylchloride/acryl caprolactone copolymer resin particle (3.1 wt. % TONEM-100 acrylated caprolactone content).

FIG. 2b SEM at 500X showing a cross-sectional view of a vinylchloride/acrylated caprolactone copolymer resin particle (10.9 wt. %TONE M-100 acrylated caprolactone content).

FIG. 2c SEM at 510X showing a cross-sectional view of a vinylchloride/vinyl acetate copolymer resin particle (2.2 wt. % vinylacetate).

FIG. 2d SEM at 510X showing a cross-sectional view of a vinylchloride/ethyl hexyl acrylate copolymer resin (2.0 wt. % Ethyl hexylacrylate).

DETAILED DESCRIPTION

The novel vinyl halide copolymers of the Present invention haveadvantages over other vinyl halide copolymer compositions of the priorart in that they are easy to process and mold into final end products.More specifically, the copolymerization of acrylated caprolactone withvinyl chloride produces copolymer particles with unique morphologycharacteristics never before observed with vinyl acetate or vinyl estercopolymer resins. In particular, the vinyl chloride/acrylatedcaprolactone copolymers of this invention have superior porositycharacteristics when compared to vinyl chloride/vinyl acetate and vinylchloride/vinyl sterate copolymers made under similar conditions. Thecopolymerization of acrylated caprolactone with vinyl chloride maintainsand or may improve resin porosity levels over that of PVC homopolymer(compare, for example, FIGS. 1a, 1b and 1c). The light reflectancephotomicrographs of vinyl halide/acrylated caProlactone copolymers shownin FIGS. 1b and 1c are similar to the light reflectance photomicrographsof PVC homopolymer shown in FIG. 1a. The reflected light is a functionof the porosity of the resin sample. Glassy or non-porous resins apPearrelatively dark and crystalline as shown in FIGS. 1d and 1e.

The copolymers of the present invention comprise repeating units ofvinyl halide and acrylated caprolactone. The final copolymer resincontains from about 80 percent to 99 percent by weight of vinyl chlorideand from about 20 percent to abOut 1 percent by weight of an acrylatedcaprolactone. As used herein the term vinyl halide includes vinylchloride and vinylidene halides such as for example, vinylidenechloride. As used herein, the acrylated caprolactone repeating unit ofthe present copolymer may be represented by the following averageformula: ##STR1## wherein R is hydrogen, lower alkyl, or phenyl, R₁ andR₂ are, independently, alkylene of 1 to about 8 carbon atoms and n is 1to about 20. Lower alkyl as used herein refers to branched or straightchain alkyl groups of 1 to 6 carbon atoms. It should be evident to thoseskilled in the art that n, as used herein, represents an average of thecaprolactone molecules per acrylate group. It is also contemplated thatfractional values of n between 1 and 20 are within the scope of thisinvention.

The preferred acrylated caprolactone monomers utilized in the presentinvention may be prepared by the reaction of the appropriate acryloylalcohols, e.g., hydroxyalkyl acrylates or hydroxyalkyl alkylacrylateswith epsilon-caprolactones. Methods for preparing acrylatedcaprolactones are disclosed in copending U.S. patent application Ser.No. 046,818, filed on May 7, 1987 which is hereby incorporated byreference. Other methods for preparing acrylated caprolactones aredisclosed in U.S. Pat. No. 4,504,635. The preferred acrylatedcaprolactone comonomers are those derived from 2-hydroxyethyl acrylate,which may be represented by the following average formula: ##STR2##wherein n is 1 to 20.

The preferred acrylated caprolactones and non-acrylated caprolactoneprecursors are commercially available from various manufacturers. Forexample, acrylated and non-acrylated caprolactones are manufactured andsold by Union Carbide Corp. under the TONE® trademark. Representativeformulas are set forth below.

    ______________________________________                                        ACRYLATED AND NON-ACRYLATED -CAPROLACTONES                                    TONE ® Monomer                                                                         Approximate No. of                                                                           Approximate                                       Designation  Repeating Units (n)                                                                          Molecular Wt.                                     ______________________________________                                        XM-100       1              230                                               M-100        2              340                                               0200*        4-6            500                                               0240*        16-18          2000                                              ______________________________________                                         *Acrylated caprolactone monomer was prepared inhouse by reacting the          appropriate TONE caprolactone diol with acryloyl chloride.               

The porous copolymeric compositions of the Present invention can beprepared by conventional polymerization in which vinyl halide monomersare copolymerized with acrylated caprolactone comonomers, polymerizationcatalysts, and if desired, chain transfer agents. The comonomers may bepolymerized by any one of a variety of polymerization techniquesincluding mass polymerization, suspension Polymerization, ormicrosuspension polymerization via the polymerization reaction of theethylenically unsaturated groups of the respective monomers. Althoughthe copolymers of this invention can be polymerized via emulsionpolymerization, a porous resin is not obtained due to the small particlesize of emulsion resins. The preferred process, however, for preparingthe copolymers according to this invention is the suspensionpolymerization process. Suspension polymerization techniques arewell-known in the art as set forth in the Encyclopedia of PVC, pp.76-85, published by Marcel Decker, Inc. (1976) and need not be discussedin great detail here. Generally, the copolymers aresuspension-polymerized in an aqueous medium containing: (1) a suspendingagent consisting of one or more water-soluble polymer substances such aspolyvinyl alcohol, cellulose ether, partially hydrolyzed polyvinylacetate, vinyl acetate-maleic anhydride or partially saponifiedpolyalkyl acrylate or gelatine, and (2) a polymerization initiator.Suitable polymerization initiators are selected from the conventionalfree radical initiators such as organic peroxides and azo compounds. Theparticular free radical initiator will depend upon the monomericmaterials being copolymerized, the molecular weight and colorrequirements of the copolymer and the temperature of the polymerizationreaction. Insofar as the amount of initiator employed is concerned, ithas been found that an amount in the range of about 0.005 part by weightto about 1.00 part by weight, based on 100 parts by weight of vinylhalide comonomer being polymerized, is satisfactory. It is preferred toemploy an amount of initiator in the range of about 0.01 part by weightto about 0.20 part by weight, based on 100 parts by weight of vinylhalide monomer. Examples of suitable initiators include lauroylperoxide, benzoyl peroxide, acetyl cyclohexyl sulfonyl peroxide,diacetyl peroxide, cumeme hydroperoxides, 5-butyl peroxyneodecanoate,alpha-cumyl peroxyneodecanoate, t-butyl cumyl peroxyneodecanoate,t-butyl peroxypivalate, t-butyl Peroxyactoate, isopropyldicarbonate,di-n-propyl peroxydicarbonate, disecondary butyl peroxydicarbonate,2,2'-azobis-(2,4,-dimethyl valeronitrile), azobisisobutylnitrile,'-azo-diisobutynate and t-butyl perbenzoate, the choice depending on thereaction temperature.

The suspension polymerization process of this invention may be carriedout at any temperature which is normal for the copolymer to bepolymerized. A temperature range from about 0° C. to about 80° C. isemployed. Preferably, a temperature range from about 40° C. to about 70°C. may be employed with a range from about 50° C. to about 60° C. beingthe most preferable. So far as the temperature is within these ranges,they may be varied in the course of the polymerization. In order tofacilitate temperature control during the polymerization process, thereaction medium is kept in contact with cooling surfaces cooled bywater, brine, evaporation, etc. This is accomplished by employing ajacketed polymerization reactor wherein the cooling medium is circulatedthrough the jacket throughout the polymerization reaction. This coolingis necessary since most all of the polymerization reactions areexothermic in nature. It is understood of course, that a heating mediummay be circulated through the jacket, if necessary.

The fact that lower molecular weight copolymers may optionally beefficiently and effectively produced is one of the preferred advantagesof the present invention. By low molecular weight what is meant is thatthe inherent viscosities of the copolymers of the present inventionrange from about 0.1 to about 0.7. The inherent viscosity is arepresentative measure of the molecular weight of a polymer and isobtained in accordance with ASTM procedure No. D-1243-66. It isrecognized that the processability of vinyl halide polymers andparticularly a vinyl chloride polymer depends to a large extent upon itsaverage degree of polymerization. Polymers having relatively lowmolecular weights or low inherent viscosities are generally the easiestto fabricate because of their low melt viscosities, low shearsensitivity, good heat stability under high shear, and excellent flowcharacteristics. Because of these desirable processing characteristics,low molecular weight vinyl chloride polymers are widely used inapplications in which they are injection molded or extruded to formproducts that may have thin walls, large surface areas, and deep-drawand/or intricate surface detailed parts. They are also used asprocessing aids in high molecular weight vinyl chloride homopolymers andcopolymers.

Specifically, the preferred suspension process of this inventionutilizes a chain transfer agent (CTA) to produce the low molecularweight copolYmers of this invention. Suitable chain transfer agentsapplicable for this purpose are, for example, saturated hydrocarbons,such as n-pentane and n-hexane, saturated or unsaturated chlorinatedhydrocarbons, such as carbon tetrachloride, trichloroethylene andperchloroethylene, aldehydes, such as propionaldehyde andn-butylraldehyde and certain mercapto-containing organic compounds. Themost preferred CTA, however, comprises a composition of: (a) at leastone mercaptan chain transfer agent and optionally (b) at least onenon-polymerizable material which is miscible with the mercaptan chaintransfer agent. Suitable mercaptans for the practice of this inventioninclude water soluble mercaptans such as 2-mercaptoethanol,3-mercaptopropanol, thiopropyleneglycol, thioglycertine, thioglycolicacid, thiohydracylic acid, thiolactic acid and thiomalic acid, and thelike. Suitable non-water soluble mercaptans include isooctylthioglycolate, n-butyl 3-mercaptopropionate, n-butyl thioglycolate,glycol dimercaptoacetate, trimethylolpropane trithioglycolate,bis-(2-mercaptoethyl) ether, alkyl mercaptans, and the like. The mostpreferred mercaptan for use in the present invention is2-mercaptoethanol (2-ME), however, any chain transfer agent having oneor more mercapto (--SH) group(s) would be acceptable.

The chain transfer composition may be Pre-mixed with the comonomer toencapsulate the mercaptan chain transfer agent before its introductioninto the reactor. Alternatively, the chain transfer agent may bepre-mixed with a non-polymerizable material which is miscible with thechain transfer agent and is substantially insoluble in water. The termnon-polymerizable as used herein means that the material does not form apart of the vinyl polymer backbone in the sense that a traditionalcomonomer would form. The non-polymerizable material may, in some cases,graft polymerize onto the vinyl polymer chain but this is not normallyconsidered a copolymer. The term substantially insoluble in water asused in this specification means that the materials have less than 5%solubility in water. The non-polymerizable material may be a monomer,oligomer or a polymer. Suitable non-polymerizable materials includedioctyl phthalate, low molecular weight poly (caprolactone),polysilicones, esters of glycerols, polyesters, water insoluble estersof fatty acids with --OH terminated polyoxyethylene andpolyoxypropylene, esters of polyols, esters of monoacids and polyacids,esters of organic polyphosphates, phenyl ethers, ethoxylatedalkylphenols, sorbitan monostearate and sorbitan monooleate and othersorbitol esters of fatty acids. Usually, the chain transfer compositionmust contain at least an equal amount in weight of non-polymerizablematerial as chain transfer agent in order to encapsulate or host thechain transfer agent. Preferably, the composition contains at leasttwice as much weight of non-polymerizable material as chain transferagent.

The amounts of chain transfer agent employed in the practice of both thecomonomer and non-polymerizable material encapsulant embodiments of thepresent invention range from 0.05 to 2.0 phm by weight per 100 phm ofvinyl halide comonomer. Preferably from 0.1 to 1.0 phm by weight per 100phm of vinyl halide comonomer may be employed. Most preferably 0.1 to0.8 phm by weight per 100 phm of vinyl halide comonomer may be utilized.The chain transfer agent may be added to the reaction medium before theonset of polymerization or it may be metered in during the course of thepolymerization reaction in combination with the comonomer ornon-polymerizable material.

The terms "encapsulation", "encapsulate" and "encapsulating" as usedherein mean that the CTA is homogeneously mixed with the comonomer ornon-polymerizable material.

The preferred polymerization initiators utilized in the process forpreparing the low molecular weight copolymers of the present inventionare alpha-cumyl peroxyneodecanoate, t-cumyl peroxyneodecanoate, t-butylperoxypivalate and t-amyl peroxyneodecanoate or combinations thereof.Most preferably, a dual initiator composition comprising alpha-cumylperoxyneodecanoate and t-butyl peroxypivalate is utilized as theinitiator. This initiator sYstem results in a reduced residual initiatorlevel in the final product and a shorter high temperature history due tofaster reactions.

The concentration of acrylated coprolactone comonomer in thepolymerization medium can range from about 1 to about 20 phm by weightbased upon 100 phm by weight of vinyl chloride monomer. The polymerizedcopolymer contains from about 1 to about 20 percent by weight ofacrylated caprolactone. Preferably the polymerized copolymer containsfrom about 3 to about 10 weight percent of acrylated caprolactone. Inorder to obtain a heterogenous copolymer (e.g. to randomize thedistribution of acrylated comonomer units along the copolymer backbone),it is preferable to meter the acrylated caprolactone comonomer into thereaction medium during the course of the polymerization. Of course, if alow molecular weight copolymer is desired, the appropriate CTA isutilized in the reaction medium as previously set forth.

It has been found in accordance with the present invention that theporosity level of the copolymer decreases as the caprolactone comonomercontent goes beyond 10 weight percent of the copolymer. Additionally,the fusion of primary resin particles occurs and begins to increase ascomonomer levels reach beyond 10 weight percent of the comonomer. Asindicated above the preferred polymerization temperature is about 50° C.to about 60° C. It has also been found that copolymers prepared athigher temperatures have less porosity due to the increased fusion ofprimary particles.

The copolymeric resins obtained from the process of the presentinvention may also contain pigments, fillers, stabilizers andplasticizers and the like which are conventionally present in PVCmolding compositions in conventional quantities. In preparing moldingcompositions the ingredients are mixed by conventional procedures usedin the production of molded products. For example, the desired resincomposition containing the copolymer resins of the present invention ishomogeneously kneaded by a mill roll, a Banbury mixer, an extruder orthe like, and thereafter is fed in the molded step of calendering,extrusion, injection or pressing. In calendering the composition iscontinuously fed to a calender and calendered into a film or sheet. Inthe case of extrusion molding, injection molding or press molding, thekneaded composition may be molded after it is pelletized. The moldingconditions herein are the same as the conventional processing conditionsfor PVC and any specific conditions are not required.

As described hereinabove, the vinyl chloride/acrylated caprolactonecopolymers of the present invention are excellent from the point that aneasily plasticized vinyl chloride copolymer is obtained having excellentphysical properties and amenable to processing to form molded products.

Various vinyl chloride copolymer resins and compositions within thescope of the present invention are illustrated in the followingexamples. While these examples will show one skilled in the art how tooperate within the scope of this invention, they are not to serve as alimitation on the scope of the invention for such scope is defined onlyin the claims. It is pointed out that in the following examples, andelsewhere in the present specification and claims, all percentages andall parts are intended to express percent by weight and parts by weightunless otherwise clearly indicated.

EXAMPLES 1-7

100 phm of VCM, 150 phm of deionized (D.I.) water, 0.08 to 0.15 phm ofhydroxypropyl methylcellulose suspending agent, 0.8 to 0.15 phm ofpolyvinyl alcohol (PVA), 25-50% hydrolyzed and the amounts of variouscomonomers, chain transfer agent (CTA) and alpha-cumyl peroxyneo-deconoate/t-butyl peroxypivalate (CPND/TBPP) polymerizationinitiator given in Table I were introduced into a 3L capacity reactorequipped with an agitator. The CTA was pre-mixed with the comonomerprior to charging into the reactor. The ingredients were charged intothe reactor in the following combinations and order; (1) D.I. H₂ Oinitiators/methylcellulose, (2) oomonomer/CTA, (3) VCM/PVA. Thesuspension polymerization was conducted at a temperature of 70° C. underagitation at 550 rpm until the reaction was complete. The copolymerresins were then recovered, stripped, washed, dried, and characterizedfor inherent viscosity (I.V.), average particle size (APS), particlesize distribution (PSD) and Mercury intrusion porosity. I.V. wasmeasured per ASTM procedure D-1243, APS and PSD were determined bystandard screen analysis and Hg porosity per ASTM D-2873 . The resultsare set forth in Table I.

                                      TABLE I                                     __________________________________________________________________________    Comonomer    CTA                       Hg                                     Example  Level                                                                             2-Me                                                                              TBPP/CPND                                                                             Conv.                                                                              I.V.                                                                             APS                                                                              PSD                                                                              Porosity                               No.  Type                                                                              (phm)                                                                             (phm)                                                                             (phm)   (Wt %)                                                                             (m)                                                                              (%)                                                                              (%)                                                                              (ml/g)                                 __________________________________________________________________________    l    VAc 2.5 0.5 0.07/0.06                                                                             65   0.375                                                                            85 97 0.038                                  2    VAc 7.5 1.0 0.12(a)/0.10                                                                          75   0.438                                                                            117                                                                              77 0.076                                  3    VAc 10  0.1 0.065/0.05                                                                            72   0.469                                                                            95 37 0.021                                  4    TONE                                                                              2.5 0.2 0.075/0.06                                                                            76   0.413                                                                            92 42 0.128                                       M-100                                                                    5    TONE                                                                              5.0 0.2 0.07/0.06                                                                             66   0.455                                                                            85 39 0.101                                       M-100                                                                    6    TONE                                                                              7.5 0.2 0.06/0.05                                                                             49   0.426                                                                            189                                                                              32 0.368                                       M-100                                                                    7    TONE                                                                              5.0  0.20                                                                             0.075/0.055                                                                           75   0.505                                                                            138                                                                              68 0.208                                       XM101                                                                    __________________________________________________________________________     (a) Made at 60° C. TBPP was replaced with tamyl peroxyneodecanoate     VAc = vinyl acetate                                                      

EXAMPLES 8-12

The copolymerization of vinyl chloride with acrylated caprolactonesproduces copolymers with a high degree of porosity relative tocoPolymers of other vinyl esters. The copolymer thusly produced could beplasticized to a high degree as is common with PVC homopolymer.

100 phm of VCM, 150 phm of D.I. water, 0.035 phm high hydrolysis PVA(85% hydrolyzed), 0.06 phm PVA (45-55% hydrolyzed), 0.045 phm ofhydroxypropyl methylcellulose suspending agent, 0.045 phm of EHPpolymerization initiator and the amounts of TONE M-100 comonomer givenin Table II were introduced into a 55L reactor equipped with anagitator. The comonomer was metered into the reactor between 0 to 55%polymer conversion. The suspension polymerization was conducted at 56°C. under agitation at 500 rpm until complete. The copolymer resins wererecovered from the reactor and stripped, dried, and characterized forI.V., APS, PSD and as Hg porosity set forth in Examples 1-7. The resultsare given in Table II.

EXAMPLES 13-18

100 phm of VCM, 150 phm D.I. water, 0.10 phm of a methylcellulosesuspending agent, 0.08 phm PVA (25% hydrolyzed), 0.012 to 0.020 phm/0.03to 0.036 phm of TBPP/CPND polymerization initiator and the amounts ofTONE M-100 comonomer given in Table II were introduced into a 55Lreactor equipped with an agitator. The PVA was pre-mixed with the VCMand the comonomer was metered into the reactor during thepolymerization. The suspension polymerization was conducted at 70° C.under agitation at 300 rpm. Upon completion of the polymerization, thecopolymer resins were recovered from the reactor and stripped, dried,and characterized as in Examples 8-12 above. Results are set forth inTable II.

                                      TABLE II                                    __________________________________________________________________________           Comonomer                 HG                                                      Level                                                                             Conversion APS                                                                              PSD Porosity                                     Example No.                                                                          Type                                                                              (phm)                                                                             (wt. %)                                                                              I.V.                                                                              (um)                                                                             (%) (ml/g)                                       __________________________________________________________________________    PVC    --  --  --    0.945                                                                              167                                                                              --  0.231                                         8     VAc 7.5 75    0.386(a)                                                                           143                                                                              40  0.034                                         9     VAc 8.0 85    0.648(b)                                                                            76                                                                              49  0.097                                        10     TONE                                                                              5.0 75    1.22 122                                                                              28  0.257                                               M-100                                                                  11     TONE                                                                              9.0 77    1.00 158                                                                              33  0.234                                               M-100                                                                  12     TONE                                                                              2.5 81    1.00 178                                                                              27  0.241                                               M-100                                                                  PVC    --  --  66     .668                                                                               82                                                                              55  0.193                                        13     TONE                                                                              2.5 78    0.715                                                                               92                                                                              35  0.170                                               M-100                                                                  14     TONE                                                                              5.0 70    0.836                                                                               80                                                                              52  0.221                                               M-100                                                                  15     TONE                                                                              9.0 78    0.818                                                                              109                                                                              19  0.113                                               M-100                                                                  16     VS  2.5 75    0.537(c)                                                                           120                                                                              48  0.092                                        17     VS  5.0 65    0.456(c)                                                                            81                                                                              51  0.093                                        18     VAc 10.0                                                                              80    0.413(d)                                                                           117                                                                              204 0.024                                        __________________________________________________________________________     (a) Made at 60° C. with 1.0 phm 2ME using TBPP/tamyl                   peroxyneodecanoate initiator                                                  (b) Made at 55°  C. with 0.14 phm 2ME                                  (c) Made with 0.10 phm 2ME                                                    (d) Made with 0.334 phm 2ME                                              

EXAMPLES 19-23

The suspension polymerization of VCM with various comonomers was carriedout following the procedure similar to that set forth in Examples 1-7. A2-ME CTA molecular weight modifier was optionally employed. The reactionconditions, comonomers and properties of the resultant copolymers areset forth in Table III.

                                      TABLE III                                   __________________________________________________________________________    Comonomer            Reaction            Hg                                   Example      Level                                                                             2-ME                                                                              Temp/Time                                                                            Conv.  APS                                                                              PSD                                                                              Porosity                             No.  Type    (phm)                                                                             (phm)                                                                             (°C./Min.)                                                                    (wt %)                                                                            I.V.                                                                             (um)                                                                             (%)                                                                              (ml/g)                               __________________________________________________________________________    19   TONE XM-101                                                                           2.5 0.20                                                                              70/290 66  0.347                                                                            101                                                                              63 0.167                                20   TONE XM-101                                                                           9.0 --  70/310 67  P.S.                                                                              82                                                                              53 0.146                                21   TONE XM-101                                                                           15.0                                                                              0.40                                                                              70/193 68  P.S.                                                                             208                                                                              61 0.199                                22   TONE M-240                                                                            3.7 --  82/236 72  0.479                                                                             87                                                                              41 0.100                                23   TONE M-0200                                                                           3.7 --  70/330 83  P.S.                                                                             115                                                                              28 0.172                                __________________________________________________________________________     P.S. = partially soluble                                                 

EXAMPLES 24-26

Vinyl chloride/acrylated caprolactone (TONE M-100) copolymer resins wereprepared as set forth in Examples 8-12. The copolymer resins werecompounded in accordance with the following recipe (parts are given byweight): 100 parts copolymer resin, 60 parts DOP plasticizer, 5 partsepoxidized linseed oil plasticizer, 3 parts calcium-zinc stablizer and0.3 parts stearic acid stabilizer. The resins and compound ingredientswere processed on a two roll mill at 320° F. for 2 minutes. Themechanical properties of the compounded resins are summarized in TableIV.

                  TABLE IV                                                        ______________________________________                                                   Example                                                            Properties   PVC      24       25     36                                      ______________________________________                                        Comonomer content                                                                          0        2.95     6.35   10.88                                   (wt. %)                                                                       Tensile Strength (psi)                                                                     2083     1994     1859   1640                                    (ASTM D-412)                                                                  Modulus at 100% (psi)                                                                      975      908      837    673                                     Max. Elongation (%)                                                                        398      382      341    334                                     Young Modulus (psi)                                                                        1302     1173     1039   788                                     Brittleness (°C.)                                                                   -35      -33.5    -34.5  -39                                     (ASTM D-746)                                                                  Clash-Berg Modulus                                                                         46,436   45,830   39,932 36,417                                  at - 35° C. (psi)                                                      (ASTM D-1043)                                                                 Stiffness Temp (°C.)                                                                -36.59   -34.79   -36.50 -37.27                                  at 45,000 (psi)                                                               Hardness - "A"                                                                             74       72       68     62                                      (ASTM D-240)                                                                  Graves Tear  285      250      210    210                                     (mg/1000 rev.)                                                                (ASTM D-1004)                                                                 Oil Resistance                                                                             -22.17   -23.0    -22.83 -22.65                                  (% vol. change)                                                               (ASTM D-471)                                                                  Compression Set                                                                            74.62    76.86    79.76  81.08                                   (% @ 22 hrs./100° C.)                                                  (ASTM D-395)                                                                  Extrusion Rate                                                                             61       60       56     55                                                   (329° F.)                                                                       (325° F.)                                                                       (322° F.)                                                                     (326° F.)                        ______________________________________                                    

EXAMPLES 27-29

Vinyl chloride/acrylated caprolactone (TONE M-100) copolymer resinscontaining the amount of acrylated caprolactone set forth below wereprepared 5 according to Examples 8-12. The resins were compounded andmilled into films (7 mills thick) and then evaluated for fish-eyecontent. The copolymer films were all rated film grade No. 1.

    ______________________________________                                        Example     Comonomer (phm)                                                                             Grade No.                                           ______________________________________                                        27          2.5           1                                                   28          5.0           1                                                   29          9.0           1                                                   ______________________________________                                    

EXAMPLE 30 OPTICAL MICROSCOPY (LIGHT REFLECTANCE)

PVC, vinyl chloride/vinyl acetate and vinyl chloride/acrylatedcaprolactone resins were each mounted to glass microscope slides.Photographs were taken at 44× magnification using reflected light tostudy the relative light reflectance of each resin. In general, glassyresins permit light to pass through and appear dark because light is notreadily reflected. Porous resins, due to their rough internalmorphologies, reflect light and therefore appear brighter under themicroscope.

The photographs of FIGS. 1a through 1e show that the vinylchloride/acrylated caprolactone coPolymer resins of this invention aresimilar to PVC homopolymer in light reflectance whereas the prior artcopolymers (vinyl chloride/vinyl acetate) are glassy in appearance.

EXAMPLE 31 SEM MICROSCOPY

The surface and internal morphologies of the resins of the presentinvention were studied via scanning electron mocroscopy. Vinylchloride/vinyl acetate and vinyl chloride/ethylhexyl acrylate copolymerresins were also studied for comparative purposes. Micrographs weretaken at various magnifications to show relative particle sizes,particle shapes, surface textures and internal morphology.

Cross-sectional views were obtained by microtoming resin particles whichwere previously embedded in a metal alloy. From examination of thecross-sections of the resins, the internal porosity and the size of theprimary particles were evaluated as well as the particle shape and sizedistribution. FIGS. 2a through 2d show the comparative morphologies ofthe resin particles.

While the present invention has been described in terms of its specificembodiments, certain modifications and equivalents will be apparent tothose skilled in the art and are intended to be included within thescope of the present invention, which is to be limited only by the scopeof the appended claims.

What is claimed is:
 1. A vinyl halide copolymer having a Hg porosity ofat least about 0.10 ml/g as measured by ASTM D-2873 comprising repeatingunits derived from vinyl halide monomer and acrylated caprolactonemonomer, wherein said vinyl halide is present in an amount from about 80to about 99 percent by weight and said acrylated caprolactone is presentin the amount of about 20 to 1 percent by weight.
 2. The copolymer ofclaim 1 wherein said acrylated caprolactone repeating unit isrepresented by the following average formula: ##STR3## wherein R ishydrogen, lower alkyl or phenyl and R₁ and R₂ are, independently,alkylene of 1 to about 8 carbon atoms and n is 1 to
 20. 3. The copolymerof claim 2 wherein R is hydrogen, R₁ is ethylene, R₂ is pentylene and nis 1 to
 20. 4. The copolymer of claim 2 wherein said vinyl halide isvinyl chloride, R₁ is ethylene, R₂ is pentylene and n is 1 to
 20. 5. Avinyl halide copolymer having a Hg porosity of at least about 0.10 ml/gas measured by ASTM D-2873 comprising repeating units derived from vinylchloride monomer and acrylated caprolactone monomer, wherein said vinylchloride monomer is present in an amount from about 80 to about 99weight percent and said acrylated caprolactone monomer is present in theamount from about 20 to about 1 weight percent wherein said acrylatedcaprolactone repeating unit is represented by the following averageformula: ##STR4##
 6. A vinyl chloride copolymer having a Hg porosity ofat least about 0.10 ml/g as measured by ASTM D-2873 comprising thereaction product derived from vinyl chloride monomer and acrylatedcaprolactone monomer, wherein said vinyl chloride monomer is present inthe amount of about 100 phm by weight and said acrylated caprolactonemonomer is present in the amount from about 1 to 20 phm by weight of thevinyl halide.
 7. A low molecular weight vinyl halide copolymer having aHg porosity of at least about 0.10 ml/g as measured by ASTM D-2873comprising repeating units derived from vinyl halide monomer andacrylated caprolactone monomer, wherein said vinyl halide is present inan amount from about 80 to about 99 percent by weight and said acrylatedcaprolactone is present in the amount of about 20 to 1 percent byweight.
 8. The copolymer of claim 7 wherein said acrylated caprolactonerepeating unit is represented by the following average formula: ##STR5##wherein R is hydrogen, lower alkyl or phenyl and R₁ and R₂ are,independently, alkylene of 1 to about 8 carbon atoms and n is 1 to 20.9. The copolymer of claim 8 wherein said vinyl halide is vinyl chloride,R₁ is ethylene, R₂ is pentylene and n is 1 to
 20. 10. The copolymer ofclaim 8 wherein R is hydrogen, R₁ is ethylene, R₂ is pentylene and n is1 to
 20. 11. A low molecular weight vinyl halide copolymer having a Hgporosity of at least about 0.10 ml/g as measured by ASTM D-2873comprising repeating units derived from vinyl chloride monomer andacrylated caprolactone monomer, wherein said vinyl chloride monomer ispresent in an amount from about 80 to about 99 weight percent and saidacrylated caprolactone monomer is present in the amount from about 20 toabout 1 weight percent and said acrylated caprolactone repeating unit isrepresented by the following average formula: ##STR6##